One of the scariest situations I have encountered is to learn that my brain sometimes forgets to trigger my breathing while I’m sleeping. It is called Central Sleep Apnea and it is different from Obstructive Sleep Apnea that typically is related to snoring.

Central apnea is a ‘systems disorder’ in that the nervous system fails to trigger the breathing reflex. Obstructive apnea is a ‘mechanical disorder’ caused by blockage of the respiratory airways as the soft palate and the tongue relax and collapse into the airway reducing or stopping the airflow. Obstructive apnea is usually associated with snoring. Central apnea is not.

In my case, I have both obstructive and central apnea. Both affect my oxygen saturation in my blood when I sleep, and both can disrupt the quality of my sleep cycles. My central apnea may be a result of my 2012 Wallenberg’s Stroke (AKA: Wallenberg’s Syndrome.) This is a stroke affecting the medulla, or brainstem that controls automatic body functions such as breathing.

Obstructive sleep apnea is relatively common; however, central apnea is not as common. In addition, obstructive apnea is effectively treated by using a CPAP or BiPAP machine during sleep to force pressure into the airway. Central apnea can be improved by this treatment; however, neither a CPAP, nor a BiPAP machine are designed to recognize a lack of breathing; therefore, a patient with central apnea may still have an issue with low oxygen saturation because the carbon dioxide is not being expelled from the lungs.

Unfortunately, some pulmonary medical professionals involved in diagnosing and treating sleeping disorders focus on obstructive apnea because it is more common, and it is effectively treated with a machine. Central apnea may have fewer events per night than obstructive apnea and when a medical professional observes that most of the apneas are resolved with a CPAP or BiPAP machine, it could be easy for them to view the remaining central apnea events as insignificant.

However, if a patient has central apnea, his brain may still be starving for oxygen even if the obstructive apnea events are completely resolved. The only way to determine this is for the physician to do a follow-up oximetry study to determine if the oxygen saturation of the bloodstream is at normal levels after treatment of the obstructive apnea has begun.

Central apnea can also result in death. There have been documented cases (SEE below) of a patient dying in their sleep (Ondine’s Curse) within days or weeks of a Wallenberg’s stroke. The assumed cause is a failure to breathe.

The only way to determine central apnea is for the patient to undergo a sleep study; however, it is important to remember that not all sleep study programs recognize central apnea as a significant issue. If the patient has both obstructive and central apnea, they may assume that treatment of the obstructive apnea issue resolves the problem. It is vital that a follow-up nighttime oximetry test be done to determine if the oxygen saturation is resolved by the use of a CPAP or BiPAP machine.

My apnea issues were undiagnosed for five years after my Wallenberg’s Stroke. Hopefully, the neurological medical community will someday require a sleep study for every Wallenberg’s Syndrome patient as part of the best practices for stroke patients. Post-stroke apneas seem to be overlooked because they don’t present obvious symptoms unless the patient dies.